Born in Canada of Irish and Scottish descent, McLoughlin was trained as a physician. He became a prominent figure in the Hudson Bay Company and was sent to Oregon country, where for two decades he ran the company (which governed the territory) from its headquarters at Fort Vancouver on the Columbia River. He supported both Protestant and Catholic missionary activity, and he converted from Anglicanism to Catholicism in 1842. He left the company in 1846 and lived from then on at his home in Oregon City, which he founded. His later life was troubled by a land dispute, concerning which he was posthumously vindicated.